The problem is with crew rest areas, or lack thereof, on the 2-class 767-300 that United wants to use on that route. UA's internal news-source said that they are suspending the route, which means it will be back. The main problem is that United's pilot contract does not provide for reliever pilots on domestic operations. Though HNL is a good 8.5 hours from ORD, it is still domestic (Hawaii is the 50th state). The DC10-30 doesn't face the same problem as the 767 because the 10 is a three crew airplane, so bingo, third pilot. The 767 only has two pilots, so they need a third.